Apparatus and method for cleaning and de-icing

ABSTRACT

A windshield heated liquid spray assembly including a liquid heating assembly and a heated liquid spray assembly operative to spray the heated liquid onto a windshield, the liquid heating assembly including a liquid heating chamber, at least one heating element disposed in the liquid heating chamber and at least one heat dissipator in heat conduction contact with the at least one heating element, the at least one heat dissipator at least partially defining at least one liquid flow channel and being operative to transfer heat from the at least one heating element to the liquid flowing through the at least one liquid flow channel.

REFERENCE TO RELATED APPLICATIONS

Reference is made to U.S. Provisional Patent Application Ser. No.60/544,438, filed Feb. 12, 2004 and entitled “Apparatus and Method forLow Temperature De-Icing,” and U.S. Provisional Patent Application Ser.No. 60/642,233, filed Jan. 6, 2005 and entitled “Apparatus and Methodfor Low Temperature De-Icing” the disclosures of which are herebyincorporated by reference and priority of which are hereby claimedpursuant to 37 CFR 1.78(a) (4) and (5)(i).

Reference is also made to applicant's copending PCT Application Ser. No.PCT/IL03/00854 filed Oct. 21, 2003, the disclosure of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

The following publications are believed to represent the current stateof the art:

U.S. Pat. Nos. 6,199,587; 6,164,587; 5,988,529; 5,947,348; 5,927,608;5,509,606; 5,383,247; 5,354,965; 5,254,083; 5,118,040; 5,012,977;4,106,508; 4,090,668 and 3,979,068.

Published PCT Applications: WO 02/092237, WO 00/27540, WO 98/58826.

SUMMARY OF THE INVENTION

The present invention seeks to provide improved apparatus and method forcleaning or de-icing vehicle elements.

There is thus provided in accordance with a preferred embodiment of thepresent invention a windshield heated liquid spray assembly including aliquid heating assembly and a heated liquid spray assembly operative tospray heated liquid onto a windshield, the liquid heating assemblyincluding a liquid heating chamber, at least one heating elementdisposed in the liquid heating chamber and at least one heat dissipatorin heat conduction contact with the at least one heating element, the atleast one heat dissipator at least partially defining at least oneliquid flow channel and being operative to transfer heat from the atleast one heating element to the liquid flowing through the at least oneliquid flow channel.

There is also provided in accordance with another preferred embodimentof the present invention a windshield heated liquid spray assemblyincluding a liquid heating assembly and a heated liquid spray assemblyoperative to spray heated liquid onto a windshield, the liquid heatingassembly including a liquid heating chamber, at least one heatingelement disposed in the liquid heating chamber and an electrical powersupply connection to the at least one heating element, the electricalpower supply connection including a meltable conductor portion in heatconductive contact with the liquid heating chamber and being operativeto melt, and thus interrupt supply of electrical power to the at leastone heating element in response to heating of liquid in the liquidheating chamber above a predetermined temperature.

There is further provided in accordance with yet another preferredembodiment of the present invention a windshield heated liquid sprayassembly including a liquid heating assembly, a liquid temperaturesensor operative to sense a temperature of liquid heated by the liquidheating assembly, a heated liquid spray assembly operative to spray theheated liquid onto a windshield and a controller operative to controloperation of the spray assembly in accordance with the temperaturesensed by the liquid temperature sensor, the controller providing atleast one first spray instance beginning when the liquid temperature isat a first temperature and terminating when the liquid temperature is ata second temperature, below the first temperature, and at least onesecond spray instance terminating when the liquid temperature is at athird temperature, below the second temperature.

Preferably, the windshield heated liquid spray assembly also includes atemperature sensor operative to sense an ambient temperature outside ofthe liquid heating assembly. Additionally, the third temperature isdetermined by the controller based on the ambient temperature.

Additionally, the controller is operative to terminate the at least onefirst spray instance if the second temperature in not reached within apredetermined time. Additionally or alternatively, the controller isoperative to terminate the at least one second spray instance if thethird temperature in not reached within a predetermined time.

Preferably, the at least one second spray instance begins when theliquid temperature is at the first temperature.

Additionally, the liquid heating assembly also includes an electricalpower supply connection to the at least one heating element, theelectrical power supply connection including a meltable conductorportion in heat conductive contact with the liquid heating chamber andbeing operative to melt, and thus interrupt supply of electrical powerto the at least one heating element in response to heating of liquid inthe liquid heating chamber above a predetermined temperature.

Preferably, the windshield heated liquid spray assembly also includes atleast one heat dissipator in heat conduction contact with the at leastone heating element, the at least one heat dissipator at least partiallydefining at least one liquid flow channel and being operative totransfer heat from the at least one heating element to the liquidflowing through the at least one liquid flow channel.

Preferably, the windshield heated liquid spray assembly also includes aliquid temperature sensor operative to sense a temperature of liquidheated by the liquid heating assembly. Preferably, the at least one heatdissipator is configured and operative to enhance homogeneity of heatingof the liquid in the liquid heating chamber, whereby the temperaturesensed by the liquid temperature sensor is generally representative ofthe temperature of the liquid within the liquid heating chamber.

Additionally or alternatively, the at least one heat dissipator isconfigured to be non-uniform along at least one dimension of the liquidheating chamber. Preferably, the at least one heat dissipator isconfigured to extend along a longitudinal axis, which is intended to bealigned vertically and is non-uniform along the longitudinal axis,thereby to enhance homogeneity of heating of the liquid therealong.

Preferably, the at least one heat dissipator includes at least oneaperture communicating with the at least one liquid flow channel.

Preferably, the at least one heat dissipator is located within theliquid heating chamber to define at least one fluid flow gap.Additionally, the at least one fluid flow gap causes fluid flow withinthe liquid heating chamber in multiple directions. Additionally oralternatively, the at least one heat dissipator is configured to extendalong a longitudinal axis and wherein the fluid flow in multipledirections includes fluid flow in opposite longitudinal directions alongthe longitudinal axis. Preferably, the fluid flow in multiple directionsprovides enhanced homogeneity of temperatures of the liquid in theliquid heating chamber.

There is even further provided in accordance with still anotherpreferred embodiment of the present invention a windshield heated liquidspray assembly including a liquid heating assembly and a heated liquidspray assembly operative to spray heated liquid onto a windshield, theliquid heating assembly including a liquid heating chamber, at least oneheating element disposed in the liquid heating chamber and a liquidsupply assembly coupled to the liquid heating chamber and including avalve operative to allow liquid flow into the liquid heating chamber andto impede backflow from the liquid heating chamber and at least onebypass conduit, user selectably operative to allow the backflow tobypass the valve.

There is still further provided in accordance with another preferredembodiment of the present invention a method for spraying heated liquidonto a windshield including providing a liquid heating assemblyincluding a liquid heating chamber, at least one heating elementdisposed in the liquid heating chamber and at least one heat dissipatorin heat conduction contact with the at least one heating element, the atleast one heat dissipator at least partially defining at least oneliquid flow channel, heating the at least one heating element,transferring heat from the at least one heating element to liquidflowing through the at least one liquid flow channel and spraying theliquid heated by the liquid heating assembly onto a windshield.

These is yet further provided in accordance with yet another preferredembodiment of the present invention a method for spraying heated liquidonto a windshield including providing a liquid heating assemblyincluding a liquid temperature sensor, heating a liquid in the liquidheating assembly until a first spray cycle start temperature is sensedby the liquid temperature sensor, beginning at least one first sprayinstance when the first spray cycle start temperature is sensed by theliquid temperature sensor, terminating the first spray instance when afirst spray cycle end temperature is sensed by the liquid temperaturesensor; the first spray cycle end temperature being below the firstspray cycle start temperature, subsequently beginning at least onesecond spray instance when a second spray cycle start temperature issensed by the liquid temperature sensor and terminating the second sprayinstance when a second spray cycle end temperature is sensed by theliquid temperature sensor, the second spray cycle end temperature beingbelow the first spray cycle end temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a simplified sectional illustration of a heated liquiddischarge system suitable for use in a motor vehicle, constructed andoperative in accordance with a preferred embodiment of the presentinvention;

FIG. 2 is a simplified exploded view illustration of the heating chamberof the system of FIG. 1;

FIGS. 3A and 3B are a simplified pictorial illustration and a simplifiedtop view illustration of the heating chamber of FIG. 2;

FIG. 4A is a simplified sectional illustration of the heating chamber ofFIGS. 2-3B, taken along lines IVA-IVA in FIG. 3B, illustrating fluidflow therewithin;

FIG. 4B is a simplified top view of the liquid heating chamber of FIGS.2-3B, illustrating fluid flow therewithin;

FIGS. 5A and 5B are, respectively, simplified sectional and top viewillustrations of a liquid heating assembly suitable for use in theheated liquid discharge system of FIG. 1 in accordance with anotherpreferred embodiment of the present invention;

FIGS. 6A and 6B are, respectively, simplified sectional and top viewillustrations of a liquid heating assembly suitable for use in theheated liquid discharge system of FIG. 1 in accordance with yet anotherpreferred embodiment of the present invention;

FIGS. 7A and 7B are simplified sectional illustrations of an electricalpower supply connection to the heated liquid discharge system of FIG. 1in accordance with yet another preferred embodiment of the presentinvention, prior to overheating and upon overheating, respectively;

FIG. 8 is a simplified illustration of a heated liquid discharge systemmounted in a motor vehicle, constructed and operative in accordance withanother preferred embodiment of the present invention;

FIG. 9 is a simplified timing diagram illustrating the operation of thesystem of FIG. 8; and

FIGS. 10A and 10B are simplified sectional illustrations of a heatedliquid discharge system suitable for use in a motor vehicle, constructedand operative in accordance with yet another preferred embodiment of thepresent invention, in two different operating modes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made to FIG. 1, which is a simplified illustration of aheated liquid discharge system suitable for use in a motor vehicle,constructed and operative in accordance with a preferred embodiment ofthe present invention. As seen in FIG. 1, a heated liquid dischargesystem 100 preferably includes a main assembly 102, which providesliquid heating and includes electrical and liquid flow controlfunctionalities. Main assembly 102 is preferably electrically connectedvia electrical cables (not shown) to a vehicle battery (not shown).

Main assembly 102 comprises a liquid heating chamber 104 communicatingwith a liquid inflow conduit (not shown) and a liquid outflow conduit(not shown). The liquid inflow conduit is operative to supply liquid,such as water, antifreeze or windshield cleaning liquid, from a vehicleliquid reservoir (not shown), having an associated vehicle pump (notshown), to the liquid heating chamber 104. The liquid outflow conduit isoperative to supply liquid to one or more sprayers (not shown), whichmay be located at one or more of the following vehicle locations: frontvehicle windshield, back vehicle windshield, side vehicle windows ingeneral and especially in locations providing viewing access to vehicleexterior mirrors, vehicle headlights, vehicle rear lights and vehicleexterior mirrors.

It is appreciated that the term “vehicle” as used in the context of thepresent patent application and in the claims can refer to any type ofwheeled vehicle having windows, such as an automobile or a truck, aswell as a boat or an airplane.

Main assembly 102 preferably includes a housing 106 defining a generallycircular cylindrical liquid heating chamber accommodating volume 108, inwhich is located liquid heating chamber 104, in a major portion of whichis disposed a liquid heating assembly 110. Housing 106 also preferablydefines a liquid inlet channel 112, a liquid outlet channel 114 and anaperture for housing a heated liquid temperature sensor 116, allcommunicating with liquid heating chamber accommodating volume 108.

Reference is now made additionally to FIGS. 2, 3A and 3B, whichillustrate details of the structure of liquid heating assembly 110. Asseen in FIG. 2, liquid heating assembly 110 preferably comprises acircular cylindrical outer sleeve 120 which defines liquid heatingchamber 104, and a base 122, which defines a sealing ring retainingsocket 124, arranged to retain an insulating liquid sealing ring 126(FIG. 1). A plurality of heating elements, preferably two in number,designated by reference numerals 130 and 132, are located within sleeve120.

In accordance with a preferred embodiment of the present invention, aheat dissipator assembly 140, including at least one heat dissipator,preferably encloses heating elements 130 and 132. Heat dissipatorassembly 140 includes heat dissipators 142 and 144, defining respectiveliquid flow channels 146 and 148, which are thermally and mechanicallyconnected to heating elements 130 and 132, preferably by soldering orany other suitable connection. Heat dissipator assembly 140 providesefficient heat transfer between heating elements 130 and 132 and liquidflowing through liquid flow channels 146 and 148. Heat dissipators 142and 144 preferably include multiple side apertures, designated byreference numerals 150, 152 and 154, to facilitate passage of liquidtherethrough.

It is appreciated that liquid flow channels 146 and 148 provideefficient heating of the liquid contained therein.

As seen further in FIG. 2, outer sleeve 120 preferably includes multipleapertures, designated 160, 162 and 164, to enable liquid flowtherethrough. It is appreciated that apertures 150, 152 and 154, as wellas apertures 160, 162 and 164 may be provided in any suitable quantity,location and shape to facilitate passage of liquid through outer sleeve120 and heat dissipator assembly 140. In a preferred embodiment of thepresent invention, a pair of each of apertures 160, 162 and 164 areprovided on opposite sides of a vertical axis thereof.

It is appreciated that apertures 150, 152 and 154, as well as apertures160, 162 and 164 are located and sized to provide increased homogeneityin the temperature of fluid located within liquid heating chamber 104.

Liquid heating assembly 110 preferably also includes an electrical powersupply connection 165 to base 122.

As seen further in FIG. 1, heated liquid discharge system 100 alsoincludes a liquid connector assembly 166 including a liquid inletpathway portion 168 and a liquid outlet pathway portion 170. Liquidconnector assembly 166 preferably comprises an injection molded elementwhich also defines a differential pressure bypass pathway portion 172,which is controlled by a spring loaded one-way valve 174 and whichpermits liquid flow from liquid inlet pathway portion 168 to liquidoutlet pathway portion 170 when the pressure differential thereacrossreaches a predetermined threshold, typically 0.3-0.5 bar, whichindicates the existence of a blockage in the liquid path through liquidheating chamber 104.

A valve 176 is disposed in liquid inlet pathway portion 168 upstream ofliquid heating chamber 104. Value 176 preferably includes a partialsealing element, such as a ball 177, which allows supply of liquid underpressure to the liquid heating chamber accommodating volume 108 butrestricts backflow therethrough to a relatively slow rate.Alternatively, ball 177 of valve 176 may be obviated to allow backflowat a relatively faster rate than the backflow otherwise provided byvalve 176 with ball 177.

Liquid from the vehicle reservoir is supplied to liquid heating chamberaccommodating volume 108 via liquid inlet pathway portion 168 and liquidinlet channel 112 and preferably enters liquid heating chamber 104,defined by sleeve 120, via apertures 160, 162 and 164 formed in sleeve120.

The liquid is heated in liquid heating chamber 104 and the temperatureof the liquid or the air overlying the liquid, depending on the liquidlevel, is sensed by temperature sensor 116, preferably a sensorcommercially available from EPCOS AG. Corporate Communications ofMunich, Germany, identified by Catalog No. G560/50K/F2. Temperaturesensor 116 preferably is mounted onto a printed circuit board 178 whichis mounted within housing 106 and located outside of liquid heatingchamber accommodating volume 108.

Also mounted on printed circuit board 178 is control circuitry foroperation of the main assembly 102 which is connected inter alia totemperature sensor 116 and the vehicle battery.

Reference is now made to FIGS. 4A and 4B, which are simplifiedillustrations of liquid flow within liquid heating chamber 104.

In accordance with a preferred embodiment of the present invention, heatdissipators 142 and 144 are positioned relative to heating elements 130and 132 to define liquid flow channels 146 and 148. The heating elements130 and 132 are preferably connected to the base 122, preferably bysoldering.

Heat dissipators 142 and 144 are positioned within outer sleeve 120 todefine a fluid flow gap between a lower surface 186 of the heatdissipator assembly 140 and an upper surface 188 of base 122.Additionally, walls of cylindrical outer sleeve 120 preferably extendbeyond the top 190 of heat dissipators 142 and 144, defining a fluidflow gap between the top 190 of heat dissipator assembly 140 and anupper surface 192 of the cylindrical outer sleeve 120.

The fluid flow gaps described hereinabove, between lower surface 186 andupper surface 188, and between top 190 and upper surface 192, permitfluid flow in multiple directions within liquid heating chamber 104 asdescribed hereinbelow.

As seen in FIG. 4A, heated fluid flows generally upwardly within heatdissipators 142 and 144, as shown by arrow 200, between lower surface186 of heat dissipator assembly 140 and top 190 of heat dissipatorassembly 140. Upon reaching the area of liquid heating chamber 104 aboveheat dissipator assembly 140, some of the fluid flows outside of thearea above heat dissipator assembly 140 and is drawn into a downwardflow, as shown by arrow 202. Unheated fluid entering liquid heatingchamber 104 through apertures 160, 162 and 164 flows generallydownwardly within liquid heating chamber 104 outside of heat dissipatorassembly 140, as shown by arrow 204. Upon reaching the area of liquidheating chamber 104 below heat dissipator assembly 140, some of thefluid flows inside of the area below heat dissipator assembly 140 and isdrawn into an upward flow, as shown by arrow 206.

The fluid flows indicated by arrows 200, 202, 204 and 206 in multipledirections are generated by differences in fluid temperature withinliquid heating chamber 104. Preferably, over time, the fluid flowsindicated by arrows 200, 202, 204 and 206 produce increased uniformityof the temperature of the liquid in the liquid heating chamber 104. Thearrangement of heat dissipator assembly 140 within liquid heatingchamber 104, providing fluid flows in multiple directions, providesincreased temperature uniformity and heating efficiency when compared toprior art heating units.

As seen further in FIG. 4A, liquid also flows through apertures 150, 152and 154 providing additional fluid flows shown by arrows 208 and 210. Itis appreciated that liquid entering heat dissipators 142 and 144 throughapertures 150, 152 and 154, as shown by fluid flow indicated by arrow208, is drawn partially into an upward flow, by the existing flow withinliquid flow channels 146 and 148, and partially into a downward flow,when it is at a lower temperature than liquid within liquid flowchannels 146 and 148. Similarly, liquid exiting heat dissipators 142 and144 through apertures 150, 152 and 154, as shown by fluid flow indicatedby arrow 210, is drawn partially into a downward flow, by the existingflow within liquid heating chamber 104 outside of liquid flow channels146 and 148, and partially into an upward flow, when it is at a highertemperature than liquid within liquid heating chamber 104 outside ofliquid flow channels 146 and 148.

As discussed hereinabove, the multiple fluid flows preferably providefor a generally homogenous temperature distribution within liquidheating chamber 104 and therefore measurement of the temperature of theliquid at the exit opening provides a generally representativeindication of the average temperature of the liquid within the heatingchamber 104. Managing the temperature and flow controls of heated liquiddischarge system 100, done in accordance with measuring the temperatureof the liquid at this point, provides enhanced homogeneity of thetemperature of the heated liquid in liquid heating chamber 104.

Specifically, heated liquid discharge system 100, by providing enhancedhomogeneity of liquid temperatures found therein, provides for anincreased volume of fluid being sprayed during a spraying cycle whoseduration is governed by the liquid temperature sensed by temperaturesensor 116. Accordingly, by providing enhanced homogeneity of liquidtemperatures found therein, heated liquid discharge system 100 providesan increased amount of heat energy transferred to the windshield by theheated liquid during a given spray cycle.

It is appreciated that this feature of providing generally homogenoustemperature distribution within liquid heating chamber 104 enables theheating system of the present invention to enhance heating of thewindshield while conforming to the requirements and specifications ofvehicle manufacturers, that define an upper limit to the liquidtemperature allowed for heated spraying.

Reference is now made to FIGS. 5A and 5B, which are simplified sectionaland top view illustrations of a liquid heating assembly suitable for usein the heated liquid discharge system of FIG. 1 in accordance withanother preferred embodiment of the present invention.

As seen in FIG. 5A, a liquid heating assembly 250 preferably comprises acircular cylindrical outer sleeve 252 and a base 254, which defines asealing ring retaining socket 256, arranged to retain an insulatingliquid sealing ring (not shown). A plurality of heating elements,preferably two in number, designated by reference numerals 258 and 260,are located within sleeve 252.

In accordance with a preferred embodiment of the present invention, aheat dissipator assembly 262, including at least one heat dissipator,preferably encloses heating elements 258 and 260. Heat dissipatorassembly 262 includes heat dissipators 264 and 266, defining respectiveliquid flow channels 268 and 270, which are thermally and mechanicallyconnected to heating elements 258 and 260, preferably by soldering orany other suitable connection. Heat dissipator assembly 262 providesefficient heat transfer between heating elements 258 and 260 and liquidflowing through liquid flow channels 268 and 270. Heat dissipators 264and 266 preferably include multiple side apertures, designated byreference numerals 271, 272 and 273, to facilitate passage of liquidtherethrough.

It is appreciated that liquid flow channels 268 and 270 provideefficient heating of the liquid contained therein.

Outer sleeve 252 preferably includes multiple apertures, designated 274,275 and 276, to enable liquid flow therethrough. It is appreciated thatapertures 274, 275 and 276 may be provided in any suitable quantity,location and shape to facilitate passage of liquid through outer sleeve252.

Liquid from the vehicle reservoir is supplied to liquid heating assembly250 via a liquid inlet pathway portion (not shown) and a liquid inletchannel (not shown) and preferably enters liquid heating assembly 250,defined by sleeve 252, via apertures 274, 275 and 276 formed in sleeve252.

The liquid is heated in liquid heating assembly 250 and the temperatureof the liquid or the air overlying the liquid, depending on the liquidlevel, is sensed by a temperature sensor (not shown), preferably asensor commercially available from EPCOS AG. Corporate Communications ofMunich, Germany, identified by Catalog No. G560/50K/F2.

In accordance with a preferred embodiment of the present invention, heatdissipators 264 and 266 are positioned relative to heating elements 258and 260 to define liquid flow channels 268 and 270. The heating elements258 and 260 are preferably connected to the base 254, preferably bysoldering.

Heat dissipators 264 and 266 are positioned within outer sleeve 252 todefine a fluid flow gap between a lower surface 280 of the heatdissipator assembly 262 and an upper surface 281 of base 254.Additionally, walls of cylindrical outer sleeve 252 preferably extendbeyond the top 282 of heat dissipators 264 and 266, defining a fluidflow gap between the top 282 of heat dissipator assembly 262 and anupper surface 283 of the cylindrical outer sleeve 252.

The fluid flow gaps described hereinabove, between lower surface 280 andupper surface 281, and between top 282 and upper surface 283, permitfluid flow in multiple directions within liquid heating assembly 250 asdiscussed hereinbelow.

As seen in FIG. 5A, heat dissipators 264 and 266 preferably extend alonga longitudinal axis 286 and are non-uniform, with varying thickness,along longitudinal axis 286. Preferably, longitudinal axis 286 isintended to be aligned vertically within liquid heating assembly 250.Preferably, the thickness of heat dissipators 264 and 266 is greatest inlocations nearest to base 254 and decreases along longitudinal axis 286proportionally to the distance from base 254. It is appreciated that theprovision of varying thickness provides a difference in heat transfer tofluid in regions located nearer to base 254 as compared with heattransfer to fluid in regions located more distant from base 254 and thusenhances homogeneity of liquid heating within liquid heating assembly250.

It is appreciated that the fluid flows of the liquid heating assembly250 of FIGS. 5A and 5B are similar to those described hereinabove withreference to FIGS. 4A and 4B.

Reference is now made to FIGS. 6A and 6B, which are simplified sectionaland top view illustrations of a liquid heating assembly suitable for usein the heated liquid discharge system of FIG. 1 in accordance withanother preferred embodiment of the present invention.

As seen in FIG. 6A, a liquid heating assembly 310 preferably comprises acircular cylindrical outer sleeve 320 and a base 322, which defines asealing ring retaining socket 324, arranged to retain an insulatingliquid sealing ring (not shown). At least one heating element,designated by reference numeral 330, is located within sleeve 320.

In accordance with a preferred embodiment of the present invention, atleast one heat dissipator 340 preferably encloses heating element 330.Heat dissipator 340 is preferably thermally and mechanically connectedto heating element 330, preferably by soldering or any other suitableconnection. Heat dissipator 340 provides for efficient heat transferbetween heating element 330 and liquid flowing through liquid heatingassembly 310.

Outer sleeve 320 preferably includes multiple apertures, designated 360,362 and 364, to enable liquid flow therethrough. It is appreciated thatapertures 360, 362 and 364 may be provided in any suitable quantity,location and shape to facilitate passage of liquid through outer sleeve320.

Liquid heating assembly 310 preferably also includes an electrical powersupply connection 365 to base 322.

Liquid from the vehicle reservoir is supplied to liquid heating assembly310 via liquid inlet pathway portion (not shown) and liquid inletchannel (not shown) and preferably enters liquid heating assembly 310,defined by the interior of sleeve 320, via apertures 360, 362 and 364formed in outer sleeve 320.

The liquid is heated in liquid heating assembly 310 and the temperatureof the liquid or the air overlying the liquid, depending on the liquidlevel, is sensed by a temperature sensor (not shown), preferably asensor commercially available from EPCOS AG. Corporate Communications ofMunich, Germany, identified by Catalog No. G560/50K/F2.

As seen in FIG. 6A, heat dissipator 340 preferably comprises at leastone plurality of fins 370 extending outwardly from heating element 330along a longitudinal axis 372 defined by heating element 330. Inaccordance with a preferred embodiment of the present invention, fins370 are non-uniform, preferably of varying length and thickness, asdescribed hereinbelow, along longitudinal axis 372. Preferably,longitudinal axis 372 is intended to be aligned vertically within liquidheating assembly 310. In a preferred embodiment of the present inventionthe at least one plurality of fins includes a first plurality of fins374 of a first length extending outwardly from heating element 330 and asecond plurality of fins 376 of a second length extending outwardly fromheating element 330, as seen in FIG. 6B.

As seen in FIG. 6A, preferably, the first plurality of fins 374 of afirst length and the second plurality of fins 376 of as second lengthinclude a first group of fins 380 of a first surface area, a secondgroup of fins 382 of a second surface area and a third group of fins 384of a third surface area. Fins 380, which are located nearer to base 322than fins 382 and fins 384, have a greater surface area than fins 382and fins 384, to provide additional surface area in contact with fluidflowing through liquid heating assembly 310. Fins 382, which are locatednearer to base 322 than fins 384, have a greater surface area than fins384, to provide additional surface area in contact with fluid flowingthrough liquid heating assembly 310. It is appreciated that theprovision of different groups of fins provides additional surface areain contact with fluid in regions located nearer to base 322 and enhanceshomogeneity of liquid heating within liquid heating assembly 310.

It is appreciated that, while the illustrated embodiment includes first,second and third groups of fins, groups of fins may be provided in anysuitable configuration, including two groups or more than three groups,each including different surface areas.

It is appreciated that the increased turbulence caused by fluidimpinging on fins 370 provides increased heat transfer and homogeneityin the temperature of fluid flowing through liquid heating assembly 310.

Reference is now made to FIGS. 7A and 7B, which are simplified sectionalillustrations of an electrical power supply connection to the heatedliquid discharge system of FIG. 1 in accordance with yet anotherpreferred embodiment of the present invention, prior to overheating andupon overheating, respectively.

As seen in FIGS. 7A and 7B, a liquid heating assembly 400 preferablycomprises a circular cylindrical outer sleeve 402, defining a liquidheating chamber 404. Sleeve 402 has a base 414, which defines a sealingring retaining socket 416, arranged to retain an insulating liquidsealing ring (not shown). At least one heating element, designated byreference numeral 420, is located within sleeve 420. It is appreciatedthat even though only one heating element 420 is seen in the illustratedembodiment of FIGS. 7A and 7B, the electrical power supply connection ofFIGS. 7A and 7B may be used with liquid heating assemblies including anysuitable configuration of heating elements.

In accordance with a preferred embodiment of the present invention,liquid heating assembly 400 includes an electrical power supplyconnection 430, connected to base 414, preferably by soldering.Electrical power supply connection 430 forms part of a circuit providingcurrent to heating element 420. An electric current input to heatingelement 420 is provided through an electrical connector point 432. Fromthere the current flows, preferably through a first end of heatingelement 420, towards an opposite end of heating element 420 preferablyconnected to the metal body of heating element 420, and from there tothe base 414. The current then flows through electrical power supplyconnection 430 to an electric contact 434.

Electrical power supply connection 430 preferably includes a housing440, preferably a metal housing suitable for allowing electric currentto flow through, an insulative layer 442, preferably a plastic layer,and a meltable conductor portion 444, preferably a solder portion,providing electrical connection between housing 440 and electric contact434.

As described hereinabove, under normal operating conditions, electriccurrent flows through electrical power supply connection 430 fromhousing 440, through meltable conductor portion 444 to electricalcontact 434.

Electrical power supply connection 430 provides a mechanism fordisconnecting the current flow to the heating element in the event ofoverheating within the liquid heating chamber 400, as described furtherhereinbelow.

Under normal operation, heating element 420 is activated only whenliquid heating chamber 400 already contains a supply of liquid to beheated. In the event heating element 420 is activated with only a smallquantity of liquid or no liquid in liquid heating chamber 404, liquidheating chamber 404 is likely to rapidly reach a high temperature andoverheat. The rise in temperature within liquid heating chamber 404 andheating element 420 would cause heating of base 414 which in turn wouldlead to a rise in the temperature in housing 440.

When the temperature in housing 440 exceeds the melting temperature ofthe meltable conductor portion 444 of electrical power supply connection430, the meltable conductor portion 444 melts and drips out of housing440, as seen in FIG. 7B. The melting of meltable conductor portion 444breaks the electrical circuit between housing 440 and the electricalcontact 434 and interrupts supply of electrical power to the heatingelement 420.

Electrical power supply connection 430 thus provides a one-time currentflow termination and provides protection against damage to the vehicleresulting from overheating of the liquid heating chamber 404 caused by aheating system malfunction.

Reference is now made to FIG. 8, which is a simplified illustration of aheated liquid discharge system constructed and operative in accordancewith another preferred embodiment of the present invention mounted in amotor vehicle, and to FIG. 9, which is a simplified timing diagramillustrating the operation of the system of FIG. 8, in accordance with apreferred embodiment of the present invention.

As seen in FIG. 8, an otherwise conventional motor vehicle 500 is seento incorporate a heated liquid discharge system 502 constructed andoperative in accordance with a preferred embodiment of the presentinvention. The heated liquid discharge system preferably includes a mainassembly 504, which provides liquid heating as well as electrical andliquid flow control functionalities. Main assembly 504 is electricallyconnected via electrical cables 506 and 507 to a vehicle battery 508.

A liquid inflow conduit 510 supplies liquid, such as water, antifreezeor windshield cleaning liquid, from a vehicle liquid reservoir 512,having an associated vehicle pump 514, to main assembly 504. A liquidoutflow conduit 522 supplies liquid to one or more sprayers 524, whichmay be located at one or more of the following vehicle locations: frontvehicle windshield, back vehicle windshield, side vehicle windows ingeneral and especially in locations providing viewing access to vehicleexterior mirrors, vehicle headlights, vehicle rear lights and vehicleexterior mirrors.

A vehicle operator actuation switch 530, typically located on thevehicle dashboard, is electrically coupled to main assembly 504 by acontrol conductor pair 532. A pair of vehicle computer interfaceconductors 534 and 536 interconnect the main assembly 504 to theexisting vehicle computer 538. An ignition interface conductor 540interconnects the main assembly 504 to the existing vehicle ignitionswitch. An external temperature sensor 541 is connected to main assembly504 via conductor 543.

The vehicle operator actuation switch 530 preferably provides a userinput for actuating automatic sprinkling cycles described hereinbelow.

Liquid from reservoir 512 is supplied by vehicle pump 514 to mainassembly 504 via liquid inlet conduit 510 and a liquid inlet pathwayportion 550. Liquid is supplied to sprayers 524 via a liquid outletpathway portion 554 and liquid outflow conduit 522.

Main assembly 504 preferably includes a liquid heating chamber 560 incommunication with a temperature sensor 570, preferably a sensorcommercially available from EPCOS AG. Corporate Communications ofMunich, Germany, identified by Catalog No. G560/50K/F2, and controlcircuitry for operation of the main assembly 504 which is connectedinter alia to temperature sensor 570 and the vehicle battery.

As seen in FIG. 9, system actuation is preferably initiated by a user,such as a driver of a motor vehicle, depressing actuation switch 530,typically located on the vehicle dashboard, as designated by referencenumeral 600. This actuation places the system into an automaticactivation mode. The system is operative, in this mode, to operate pump514 to execute a first spray cycle and a second spray cycle, designatedby reference numerals 602 and 604, respectively.

Upon entering automatic activation mode, heated liquid discharge system502 is operative to provide a current to heating elements, heating theliquid contained in liquid heating chamber 560, causing an increase inthe temperature sensed by sensor 570, as designated by reference numeral606.

When the temperature sensed by temperature sensor 570 reaches a firstspray cycle start temperature, 75° C. in the illustrated example, asdesignated by reference numeral 608, heated liquid discharge system 502preferably operates pump 514 to execute first spray cycle 602 anddischarge fluid through liquid outlet pathway portion 554 and liquidoutflow conduit 522 to sprayers 524. First spray cycle 602 preferablycontinues until the temperature sensed by sensor 570 reaches a firstspray cycle end temperature, lower than the first spray cycle starttemperature, 56° C. in the illustrated example, as designated byreference numeral 610. In accordance with a preferred embodiment of thepresent invention, first spray cycle start temperature and first spraycycle end temperature are selected such that the duration of first spraycycle 602 is preferably approximately four seconds, during which timethe temperature sensed by sensor 570 reaches the first spray cycle endtemperature.

Upon termination of the first spray cycle 602, the temperature sensed bysensor 570 starts to rise again due to the heating of the fluidcontained in the liquid heating chamber 560.

In accordance with a preferred embodiment of the present invention,heated liquid discharge system 502 is preferably operative to operatepump 514 to execute second spray cycle 604 when the temperature sensedby sensor 570 reaches a second spray cycle start temperature, 75° C. inthe illustrated example, as designated by reference numeral 612. It isappreciated that second spray cycle start temperature may be the same asthe first spray cycle start temperature or may be different.

Second spray cycle 604 preferably continues until the temperature sensedby sensor 570 reaches a second spray cycle end temperature, lower thanthe first spray cycle end temperature and lower than the second spraycycle start temperature, such as 5° C. in the illustrated example, asdesignated by reference numeral 614. In accordance with a preferredembodiment of the present invention, second spray cycle starttemperature and second spray cycle end temperature are selected suchthat the duration of second spray cycle 604 preferably does not exceedeight seconds, during which time the temperature sensed by sensor 570reaches the second spray cycle end temperature.

It is appreciated that heated liquid discharge system 502 may also beoperative to end first spray cycle 602 based on a first spray cyclemaximum duration, in the event that the first spray cycle endtemperature is not reached within the maximum time duration. It is alsoappreciated that heated liquid discharge system 502 may also beoperative to end second spray cycle 604 based on a second spray cyclemaximum duration, in the event that the second spray cycle endtemperature is not reached within the maximum time duration.

It is appreciated that the temperatures given are for illustrativepurposes only, and that any suitable temperature ranges may be selectedto determine the duration of the first and second spray cycles. It isappreciated that the time durations given are for illustrative purposesonly, and that any duration may be selected as the maximum time allowedfor the first and second spraying cycles 602 and 604.

In accordance with another preferred embodiment of the presentinvention, heated liquid discharge system 502 may be operative todetermine the second spray cycle end temperature as a function of anambient temperature sensed by temperature sensor 541. It is appreciatedthat determining the second spray cycle end temperature as a function ofthe ambient temperature provides an enhanced second spray cycle,particularly at very low ambient temperatures, such as below 0° C.

Reference is now made to FIGS. 10A and 10B, which are simplifiedsectional illustrations of a heated liquid discharge system suitable foruse in a motor vehicle, constructed and operative in accordance with yetanother preferred embodiment of the present invention, in two differentoperating modes.

As seen in FIGS. 10A and 10B, a heated liquid discharge system 900,similar to heated liquid discharge system 100 of FIG. 1, preferablyincludes a main assembly 902, which provides liquid heating and includeselectrical and liquid flow control functionalities. Main assembly 902 ispreferably electrically connected via electrical cables (not shown) to avehicle battery (not shown).

Main assembly 902 comprises a liquid heating chamber 904 communicatingwith a liquid inflow conduit (not shown) and a liquid outflow conduit(not shown). The liquid inflow conduit is operative to supply liquid,such as water, antifreeze or windshield cleaning liquid, from a vehicleliquid reservoir (not shown), having an associated vehicle pump (notshown), to the liquid heating chamber 904. The liquid outflow conduit isoperative to supply liquid to one or more sprayers (not shown), whichmay be located at one or more of the following vehicle locations: frontvehicle windshield, back vehicle windshield, side vehicle windows ingeneral and especially in locations providing viewing access to vehicleexterior mirrors, vehicle headlights, vehicle rear lights and vehicleexterior mirrors.

Main assembly 902 preferably includes a housing 906 defining a generallycircular cylindrical liquid heating chamber accommodating volume 908, inwhich is located liquid heating chamber 904, in a major portion of whichis disposed a liquid heating assembly 910. Housing 906 also preferablydefines a liquid inlet channel 912, a liquid outlet channel 914 and anaperture for housing a heated liquid temperature sensor 916, allcommunicating with liquid heating chamber accommodating volume 908.

Liquid heating assembly 910 preferably comprises a circular cylindricalouter sleeve 920, which defines liquid heating chamber 904, and a base922, which defines a sealing ring retaining socket 924, arranged toretain an insulating liquid sealing ring 926. A plurality of heatingelements, three in the illustrated embodiment, designated by referencenumerals 930, 931 and 932, are located within sleeve 920. It isappreciated that while the illustrated embodiment includes three heatingelements, any suitable configuration of heating elements may beprovided.

Outer sleeve 920 preferably includes multiple apertures, designated 960and 962, to enable liquid flow therethrough. It is appreciated thatapertures 960 and 962 may be provided in any suitable quantity, locationand shape to facilitate passage of liquid through outer sleeve 920 intoliquid heating assembly 910.

Liquid heating assembly 910 may also include an electrical power supplyconnection 965 electrically connected to base 922.

As seen further in FIGS. 10A and 10B, heated liquid discharge system 900also includes a liquid connector assembly 966 including a liquid inletpathway portion 968 and a liquid outlet pathway portion 970. Liquidconnector assembly 966 preferably comprises an injection molded elementwhich also defines a differential pressure bypass pathway portion 972,which is controlled by a spring loaded one-way valve 974 and whichpermits liquid flow from liquid inlet pathway portion 968 to liquidoutlet pathway portion 970 when the pressure differential thereacrossreaches a predetermined threshold, typically 0.3-0.5 bar, whichindicates the existence of a blockage in the liquid path through liquidheating chamber 904.

A valve 976 is disposed in liquid inlet pathway portion 968 upstream ofliquid heating chamber 904.

Liquid from the vehicle reservoir is supplied to liquid heating chamberaccommodating volume 908 via liquid inlet pathway portion 968 and liquidinlet channel 912 and preferably enters liquid heating chamber 904,defined by sleeve 920, via apertures 960 and 962 formed in sleeve 920.

The liquid is heated in liquid heating chamber 904 and the temperatureof the liquid or the air overlying the liquid, depending on the liquidlevel, is sensed by temperature sensor 916, preferably a sensorcommercially available from EPCOS AG. Corporate Communications ofMunich, Germany, identified by Catalog No. G560/50K/F2. Temperaturesensor 916 preferably is mounted onto a printed circuit board 978 whichis mounted within housing 906 and located outside of liquid heatingchamber accommodating volume 908.

Mounted on printed circuit board 978 is control circuitry for operationof the main assembly 902 which is connected inter alia to temperaturesensor 916 and the vehicle battery.

It is appreciated that valve 976 is similar in structure to valve 176 ofFIG. 1, including a ball 980, except that valve 976 communicates with aconduit 982 which provides an alternative flow pathway between thesprayers and the reservoir. Heated liquid discharge system 900 thusprovides two fluid flow passages for draining fluid from the sprayers tothe reservoir upon the conclusion of spraying. As seen in FIG. 10A, anend 986 of conduit 982 extends beyond an outside surface of housing 906.

A bi-directional valve assembly 1000 is connected to liquid inletpathway portion 968 and conduit 982. Bi-directional valve assembly 1000includes a bi-directional valve 1002 and conduits 1004 and 1006 andrespective couplings 1014 and 1016 which link valve 1002 with liquidinlet pathway portion 968 and end 986 of conduit 982 respectively.

Bi-directional valve 1002 preferably comprises a user positionable valvemember 1018. Bi-directional valve assembly 1000 further includes aninlet conduit 1020 for connecting heated liquid discharge system 900 tothe vehicle reservoir (not shown).

In the operating orientation shown in FIG. 10A, valve member 1018 ofbi-directional valve 1002 is located in the ‘ON’ position which permitsflow into liquid heating chamber 904 bypassing ball 980 of valve 976, asindicated by flows, designated by arrows 1030, 1032 and 1034, inaddition to flow through ball 980 of valve 976 as indicated by flows,designated by arrows 1040 and 1042. In the operating orientation of FIG.10A, heated liquid discharge system 900 supplies liquid under pressureto the liquid heating chamber 904 and allows backflow, as indicated byarrows 1030, 1032 and 1034, at a relatively fast rate.

In the operating orientation shown in FIG. 10B, valve member 1018 ofbi-directional valve 1002 is located in the “OFF” position which permitsflow into liquid heating chamber 904 through ball 980 of valve 976, asindicated by arrows 1040 and 1042. In the operating orientation of FIG.10B, valve 976 is functionally equivalent to valve 176 of FIG. 1 andallows backflow, as indicated by arrows 1040 and 1042, at a relativelyslow rate.

Heated liquid discharge system 900 thus provides user selectablebackflow functionality without requiring valve 976 to be directlyaccessed after installation in a vehicle.

It is appreciated that bi-directional valve assembly 1000 may beobviated and a cap (not shown) placed over end 986 of conduit 982. Inthis orientation heated liquid discharge system 900 allows supply ofliquid under pressure to the liquid heating chamber 904 but impedesbackflow therethrough, restricting backflow to a relatively slow rate.

It is appreciated that the systems of the present invention are suitablefor inclusion both in new vehicles and for retrofitting into existingvehicles.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove as well as modifications and variations thereof aswould occur to a person of skill in the art upon reading the foregoingspecification and which are not in the prior art.

1. A windshield heated liquid spray assembly comprising: a liquidheating assembly; and a heated liquid spray assembly operative to sprayheated liquid onto a windshield, said liquid heating assemblycomprising: a liquid heating chamber comprising a substantiallycylindrical outer sleeve disposed about a longitudinal axis; at leastone heating element disposed in said liquid heating chamber; and atleast one heat dissipator disposed in said liquid heating chamber inheat conduction contact with said at least one heating element, said atleast one heat dissipator having at least one wall at least partiallydefining at least one substantially linear liquid flow channel parallelto said longitudinal axis and having first and second open ends, said atleast one heat dissipator being operative to transfer heat from said atleast one heating element to liquid flowing through said at least oneliquid flow channel, whereby liquid flows within the at least one liquidflow channel primarily in one direction with respect to the longitudinalaxis, from the liquid heating chamber into the first open end to thesecond open end and into the liquid heating chamber, through convectionas heat is transferred to the liquid by the at least one heatdissipator.
 2. A windshield heated liquid spray assembly according toclaim 1 and also comprising a liquid temperature sensor operative tosense a temperature of liquid heated by said liquid heating assembly andwherein said at least one heat dissipator is configured and operative toenhance homogeneity of heating of said liquid in said liquid heatingchamber, whereby said temperature sensed by said liquid temperaturesensor is generally representative of the temperature of said liquidwithin said liquid heating chamber.
 3. A windshield heated liquid sprayassembly according to claim 1 and wherein the at least one wall of saidat least one heat dissipator is configured to be non-uniform inthickness along said longitudinal axis of said liquid heating chamber.4. A windshield heated liquid spray assembly according to claim 1 andwherein said at least one heat dissipator includes at least one aperturethrough the at least one wall communicating with said at least oneliquid flow channel.
 5. A windshield heated liquid spray assemblyaccording to claim 1 and wherein the liquid heating chamber furthercomprises a base connected to a first end of the cylindrical outersleeve and an upper surface connected to a second end of the cylindricalouter sleeve.
 6. A windshield heated liquid spray assembly according toclaim 5 and wherein a first fluid flow gap is formed between the firstopen end of the at least one heat dissipator and the liquid heatingchamber base, and a second fluid flow gap is formed between the secondopen end of the at least one heat dissipator and the liquid heatingchamber upper surface, whereby heated liquid circulates by convectionprimarily out the second open end into the second fluid flow gap,between the at least one heat dissipator and the liquid heating chambercylindrical sleeve, and through the first fluid flow gap into the firstopen end.